The technique of three-dimensionally reproducing such an object, e.g. in the form of a sculpture, with the aid of stored information has been known for some time. The information is generally obtained photographically, in the form of pictures taken of the object at different angles. In order to enable a faithful reproduction of the peaks and recesses of the object surface, it has already been proposed to project grids or contour lines upon that surface and to take images thereof in various relative positions of the object and a camera used for this purpose. Reference in this connection may be made, for example, to U.S. Pat. Nos. 2,015,457, 2,335,127 and 3,884,577. The last-mentioned patent teaches the projection of a horizontal luminous contour line at successive levels upon a human head to be replicated.
The scanning of an object surface with the aid of contour lines, however, does not invariably reveal all the detail required for high-fidelity reproduction. Human hair, especially when darkly colored, is a poor light reflector so that the shape of the top of the head, for example, is not always correctly reproduced with conventional techniques. Thus, it has often been necessary heretofore to reshape the automatically sculptured replica of a human head by manual retouching on the basis of additional photographs.
Artists have long practiced the reproduction of profiles of human heads in the form of silhouettes cut by scissors. Even a multiplicity of such silhouettes taken from various angles, however, will not encompass all the details needed for faithful three-dimensional representation and, in particular, will fail to reveal facial recesses characteristic of a person's physiognomy.